Such a rotary cutting tool is disclosed in U.S. Pat. No. 5,957,631. The cutting tool comprises a cutting head and tool shank each having two coupling portions and two chip flutes defined therebetween. Each coupling portion of the cutting head and tool shank has a stepped configuration with a raised base surface adjacent one flute and a lowered base surface adjacent the other flute. If the cutting head and tool shank are designed to be coupled together with both the raised and lowered base surfaces in contact, then these surfaces have to be manufactured such that the distance between them is the same to within a high degree of accuracy. If on the other hand, the cutting head and tool shank are designed to be coupled together with only one of the raised and lowered base surfaces in contact, then the coupling will be less stable.